Tsundere Thesis
by Yojimbra
Summary: Despite all evidence to the contrary Izuku Midoriya and Saiko Intelli are going to prove that they absolutely do not love each other with science or confess trying!
1. Chapter 1

Oh.

Oh no.

This couldn't possibly be right! There was simply no way that this could be the correct answer! As much as she hated to admit it she must have made a mistake somewhere. Anywhere. Any mistake in the entire thing would have been a less glaring blow to her ego than the result she was seeing in front of her.

But all of the data that she had compiled, all of it, was right.

Every single one of her calculations, even when she skewed them to fit her own bias, was pointing directly towards that one answer that filled her with dread. While also somehow making her cheeks burn and heart flutter. More data. She hated the answer but not nearly as much as she thought she would have. That was what her calculations were missing! Her own feelings! How could she forget to take those into account?

Right. Start with something simple. Simple. What on earth was considered simple in terms of romance?

Ahh! Right! Holding hands!

Marker to the board, Saiko Intelli took in a deep breath and pictured herself holding his hand. The rough texture of his hands, the firmness with which he tackled every task mixed with his sweet and kind nature that he showed to everyone besides herself. The fiery passion he talked to her with and the simple notion of being around him that infuriated her to go even further beyond more than any hero ever could.

She made a single line all the way down to the bottom of the white board and glared at it.

There was no escaping the result. Weeks upon weeks of work, coyly gathering data and being around that insufferable man that she.

That she.

That she.

That she hated! She hated every single last thing about him. His smile. His hair. His eyes. His brain. His laugh. His. His everything! Only she didn't hate him. The results proved as much. Even if she tried to not think about it her life was just brighter with him in it. She couldn't picture him out of it. She couldn't picture him not smuggly telling her that she was wrong and then showing her why. She couldn't picture their endless arguments not keeping her up for an extra hour.

Or six.

But she could picture him as something more. She could picture him holding her hand. She could picture him smiling at her. She could picture him kissing her forehead. She could picture him holding her softly. Him running his hand through her hair, him whispering in her ear and making her laugh. She could picture all of it.

That truth, that oh so inevitable truth that she had been avoiding since highschool, if not before was finally being brought up to the forefront of her thoughts where it was strangling her attention. Looking back on her life, it was so obvious. So completely obvious. She chose to go to his highschool. She chose to be in the same clubs as him. And finally, they had chosen a college to attend.

It almost felt like she had no agency in her own life and was just following him around. But she had indeed chosen to follow him around. They were rivals after all. They both acknowledge that they both worked so much better when they were near each other.

It should have been obvious from the start.

So now, it was time for her to finally admit that she-

"No!" Saiko moved over to the final answer. Hours of work and weeks of data collection vanished with a swipe of the eraser. She stared at the newly created blank streak and glared at it. She had a new objective. A new project to work on. "I'm going to make him say it first."

There was no way that she was going to admit that she was completely and totally in love with Izuku! Not until he admitted that he was completely and totally in love with her. Because if he didn't, then it wouldn't mean anything.

XXXX

"Midoriya!"

He heard her. He really really did. But she only used his last name whenever she was annoyed. And she was always annoyed at him, so annoying her further and making her even more annoyed at him really wouldn't change much. If anything it might make her get to the point faster. Plus when she was annoyed at him and they were talking, her nose would wiggle just ever so slightly and that was one of the few times that he found her to be ever so slightly attractive.

The moment Saiko walked into his view he was drawn to her with a primal need driven by more basic instincts. And it was so easy to see why. With her soft baby blue hair, piercing blue eyes, a charming smile, a killer body that was barely hidden behind her lab coat, she was a real beauty. Indeed she would be perfect with how she looked, how smart she was, how she challenged him. Or she would have been, were it not for her completely and utterly terrible personality. She really did just make him bristle at the thought of spending time with her. Even if it was one of his favorite things.

Look, he was a complicated person. As much as he hated arguing with Saiko for so long that it regularly threatened his sleep schedule, he also kind of liked it. It felt weird if they didn't have one debate that would consume at least two white boards a week. Even weirder if she didn't try and one up him whenever he made an accomplishment. Or vice versa. There was just something so satisfying about forcing her to march out of a room, her face red from another humiliating defeat.

It so made up for all those times he was forced to concede defeat to her.

"Midoriya." Saiko said more firmly from behind him. He could feel her smug aura permeating into the very molecules of his sandwich. "Stand up. I refuse to have this conversation while you are sitting down and stuffing your face."

"Then come back later." He took another bite without looking at her. Something that would only make her all the more annoyed. "Like tomorrow. Same time so I can tell you to leave again."

Okay. So as bad as Saiko's personality was, he really didn't help make her less of a raging bonfire. If anything it might be at least partially his fault she was like this. But there was no way he was taking the whole blame! She was like this ever since they met in middle school!

"No." She said curtly. "This is something that cannot be delayed any further now please. Midoriya. Stop eating your sandwich. Stand up and look at me."

Well she was bossy today. Normally that only happened when he did something to really piss her off. Or when she was going to apologize about something that really pissed him off. Saiko might be arrogant and prideful but she could swallow that pride when needed.

With a sigh Izuku stood and looked down at his ever so reluctant partner in crime. He swallowed so that his jaw wouldn't drop and rolled his shoulder to keep himself from blushing when he saw her. Seriously why did she have to be so completely breathtaking? She wasn't just a natural beauty, she was a natural beauty that knew how to make herself more beautiful with proper make-up, hair style, accessories, and just keeping herself healthy.

Completely unlike the few other women they both worked with.

Today she had a pair of atom shaped earrings that she had forced him to buy her during a contest at their highschool festival. A small tear shaped pendant she had worn since the day he first met her hung on top of her light pink blouse that complimented her light hair and contrasted with her black mini skirt that hugged her hips and those long grey leggings she wore. Her black heels only gave her two extra inches of height Which made the distance between them three inches as opposed to five.

All in all she looked like a model or actress playing the role of the pretty young scientist. Only she was the real deal.

"What is itIntelli?" He crossed his arms and raised an eyebrow at her.

Her eyes went wide and she looked at him up and down before she shook her head and regained her trail of thought that he in all likelihood had disrupted. "We need to have a talk."

Oh joy. What did he do to set her off this time? Was she going to lecture his caloric intake again? It was fine, he was going to the gym more and was currently attempting to increase his muscle mass. Was it petty that he was going out of his way to make sure that he was just as attractive as Saiko was by working out and making sure that he was physically fit?

Maybe. But it was a good kind of petty.

"Well?" he prompted again.

Saiko shook her head and rolled her shoulders closing her eyes for a moment and taking in a deep breath. When she opened up her eyes once more he felt a tingle run down his spine with those piercing dark blue eyes of hers that were so perfectly designed to lure in men such as himself.

"You. Izuku Midoriya!" She took a dramatic pose like from a manga her finger poking him in the chest. "You are completely and totally in love with me!"

He stared at her, mind trying to simultaneously process the gibberish she just said, while at the same time saving her overly dramatic pose to make fun of her for it later. That and it was kinda cute.

"Intelli. Did you hit your head or something?" He asked blinking at her.

Her face went red, all dignity gone. "What? No! I can assure you that you are in love with me Midoirya!"

"Oh yeah?" He crossed his arms and raised an eyebrow at her. "What makes you think you can do that?"

"I can prove it! With science!" She turned towards his white board, hips swaying with every single step and luring him towards the way she made that labcoat swish. "During this past week in advanced quirk physics you made 312 glances towards me in class! Coupled with that your heart rate increases when I'm around to a level of moderate exercise. And-"

"You're projecting on me aren't you?" He asked moving beside her on the white board. "If you're gathering all this data then there is only one possible conclusion Intelli! That you were worried that you were in love with me! And once you found out you were you decided that you would try to put the blame on me."

"Hardly!" She turned towards the board and began to write more numbers. "Do you recall when they forced us to dance during the last expo? I remember your heartbeat Midoriya! I thought it was oddly high at the time so I decided to investigate your feelings towards me. And the numbers don't lie! You are in love with me."

"Ha! You're just trying to cover up after yourself Intelli! And no doubt your science was skewed from your own personal bias! Here let me prove it with science!"

It didn't matter if he actually was in love with her. There was no way in hell that he was going to admit that to her! He was going to make her confess to him! But first.

"I'm going to prove that I don't love you with science!" They both shouted at once.

**AN: Holy shit. This. This was so amazing to write! Its kind of a mish-mash of Love is War and Science Types in love but also just blended into something wonderful. Guh. I love it. **


	2. Chapter 2

The profession known as cooking was just a simple matter of applied mathematics. Everything could be boiled down into ratios, from the quality of ingredients based on the molecular strains in each one, to the duration and force of stirring and mixing the ingredients. Everything had a small piece in a much larger equation that could be tuned to give the answer Saiko sought.

A chocolate so perfect that Izuku would confess after just one taste, if not from the scent alone.

That was part of the reason why she had insisted on both of them doing this in the lab. There were numerous other reasons why she wanted to do this with Izuku nearby, from keeping an eye on him, to making certain that their controlled conditions were the same, and even just that nagging desire to be near him despite how much he pissed her off had some sway in this request. But it's contribution was negligible at best.

And, in theory, the act of cooking together was inherently romantic, so the act of making romantic chocolates for each other with romantic intent should prove to be extraordinarily romantic. All she had to do was keep calm, make sure that she didn't get too worked up about Izuku making her chocolates and try not to stare at him too much.

Which was something that she thought would be easy. It was just like any other silly, petty, and completely useless competition that they found themselves in. Or so she thought. But then Izuku cheated. Right now he was doing that completely and utterly detestable act that made her entire body feel like it was about to explode with her desire. It was such a coy and clever act that she almost thought there was a completely innocent intent behind it.

But no. Izuku was a deliberate man. This was calculated. And nobody rolled their sleeves up like that! A slow, folding motion that fully displayed both of his muscular forearms, it was pure flirtation! He was desperate to get her to confess that meant that she could use it and then she could freely touch those arms and have him hold her in them and-

"Something wrong, Intelli?" Izuku asked, that smug look on his kissable face pissing her the fuck off!

With a breath to calm her outward emotions, Saiko turned to her ingredients. Two could play at this game. It wasn't as though Izuku was the only one that came with weapons. And she knew just how to use them against him. "Not at all, Midoriya. I just realized you are correct."

His eyes went wide for a second, then narrowed dangerously. "About what?"

She threw her arms back causing her lab coat to drop slightly, revealing the cute sleeveless top she had selected, it was a soft baby pink that hugged her figure the fabric was like that of a sweater with rigids built in and a slight turtleneck. Judging by Izuku's face, the sweater had its intended effect of luring Izuku's gaze onto her.

Now for the finishing touch that would leave Izuku drooling. That extra polynomial of femine charm that would turn the equation of seduction from linear to exponential! She grabbed her long blue hair, and pulled it into a high tight ponytail. This simple act showed off so many parts of her, the act of grabbing her hair was nearly a stretch, showing off her slender form, the hair itself falling into place, the exposure of several areas that Izuku rarely got to see, armpits, nape of the neck, and even showing off the jewelry she wore in her ear.

It was the perfect trump card against Izuku.

Izuku turned away from her, now focusing on his chocolate making process. His ears were red, and he had a grumpy look on his face. Of course he would. It was only natural, he had attempted to sway her with his strong muscular arms by rolling up his sleeves. And she countered by removing her lab coat, now if he were to do the same he would look like a fool.

The first victory of the day was hers!

"Is something wrong, Midoriya?" Saiko asked, leaning over to him and nearly brushing her shoulder against his.

She caught a single green eye peering at her, his cheeks were ever so slightly pink. Did her little maneuver truly have such an effect on him? Perhaps if she were to do it more often then Izuku would cave sooner. No, that would diminish its effects, she needed to be careful with this and bring it out at the right time to make Izuku drool.

"Lace."

Lace?

Why would Izuku be saying that simple word? Why did he look so distrubed by it and. And. And. She brought a hand up to where her blouse dropped. The fabric was a bit loose here so that she could have a full range of movement. It didn't take long for her to feel what Izuku was talking about. Somehow her shirt had gotten snagged on the black lace bra she was wearing and exposed the patterned when she brought her arms up.

"Oh," she muttered, turning towards her own chocolate. Her face felt flushed. It wasn't the first time she had accidentally exposed her underwear to Izuku, but the context of the situation made it just that much more embarrassing. It would appear that her ultimate weapon did have a drawback. "Please pretend you didn't see that."

Izuku simply nodded.

XXXX

Like hell he'd ever forget something like that!

Sure, it was immature, pointless and he had seen more than that, hell he'd seen her in a swimsuit last summer when they were testing a water based experiment, and that was still burned into his memory. Sure he had classified it as a moment of lust and reminding himself that Saiko was more than just an annoying know it all that refused to leave him alone, she was a beautiful woman that refused to leave him alone.

A beautiful woman that plagued his dreams with sweet whispers and that made his heart thump in his chest. A beautiful woman that he just couldn't stand losing too. As much as he liked to see her smile, he couldn't stand her smiling because she beat him.

Which was why he was going to pull out all the stops. He had rolled up his sleeves partially to distract her, it wasn't the first time he had done it, and it wasn't the first time he had caught Saiko sneaking glances at the action, but he had also done it to prepare himself for whatever she was going to throw at him.

But the tossing of her lab coat, the stretch into the ponytail, and that oh so brief flash of her black lace bra. Black lace. Did her panties match? What was her cup size? He had resisted the urge to attempt to calculate that number using only observable data if only to give himself that small satisfaction of knowledge. But that would be giving her a victory.

Even if she didn't know about it, he couldn't give her that.

So he was going to win this little chocolate making game they were playing, and he had a secret weapon. But first, information gathering.

"So, what kind of chocolate are you going to make?" He looked at her hands carefully mixing her cocoa powder mix. There was cocoa butter too, as well as milk, some sugar, and salt. "Milk chocolate?"

"How observant of you. Remember, the goal is to impress each other; I choose milk chocolate to satisfy your tastes." Saiko spoke soft, but sharp, oh so very sharp. Her blue eyes sent a chill down his spine when she looked at him, and that coy smile of her enhanced her already appealing look all the more. The sleeveless sweater look was a good one for her. "And I see that you have aimed for my preferences and went with a Dark Chocolate. But it will all be for naught."

"Oh? What makes you say that?" He narrowed his eyes at her. That damn smile of hers. Why didn't he have something like that for when he knew that he was going to win? It felt unfair. Maybe he should start throwing his shirt off and flexing when he won, no doubt Saiko would enjoy that.

It'd be fair revenge for putting the image of her in black lace underwear in his mind. Every fiber of his being wanted to see her like that in person, not just in his imagination. That would come in time though. Once she was forced to confess to him, and they dated, and they learned to tolerate each other, then, perhaps they would even go that far.

Saiko smiled and continued to stir her chocolate concoction, adding in some more of her ingredients in perfectly measured proportions. "Simple, I'm making it. And well, yours, is uhh, how to put it? Subpar?"

Never mind, he could never fall for such an arrogant and spiteful woman!

"We'll see about that!" He grabbed his own ingredients, and tossed them into the bowl. Cooking was not an exact science, something being not exact made it interesting, and just like a steak could be made in a dozen different ways with different seasoning. It wasn't that he was throwing caution to the wind. He had a plan after all.

The chocolate was melted, making the entire lab smell both bitter and sweet all at once. While his own dark chocolate smelled wonderful and was based off of his mother's own recipe he had to admit that Saiko's did smell absolutely wonderful. It almost made him feel like a kid at halloween again. Though this time he wasn't dressed as All Might.

He smiled when his chocolate was fully prepared. Now for the finishing touches.

A large amount of food had to be shipped to I-Island which made fresh fruits difficult to come by. However, there were several scientists that kept small private gardens, and they were often willing to part ways with some of their stock for a few chores. Once the tray was fully prepped Izuku brought out his secret weapon.

"Strawberries?" Saiko asked as he pulled out a fresh batch of ripe strawberries that were bursting with color. He had a few last night. They were sweet, juicy, with that slightest bit of tang that was bound to mix with his chocolate perfectly. "What are you planning, Midoriya?"

"Not just strawberries." He pulled out an orange and winked at her. Among Saiko's weaknesses in life was her fondness of oranges. He remembered her seeking out the oranges in highschool while she sipped on her tea. "Oranges too."

"My." She rolled her eyes sarcastically. "How thoughtful, though I worry that your chocolate will simply spoil such wonderful fruits."

"We'll see, it'll be better than your plain-"

Saiko reached down and pulled up something he hadn't expected. Peanut butter.

Damn. That was good. That was real good.

Saiko tapped on the lid and raised an eyebrow at him. "You were saying?"

"You're a hypocrite."

"Oh, absolutely. Now then, let's finish this business, unless you'd rather just confess to me now." She placed a careful finger right above her heart and fluttered her eyes at him.

He rolled his and began to bathe his fruit in the chocolate he prepared.

When everything was finished they both ended up with a modest plate of chocolate. And Saiko continued to play dirty. Despite her perfectionism, she had a single mark of chocolate placed upon her cheek. He didn't see it when it appeared, but he knew she placed it there on purpose in order to make herself look cute. And it did. How could that slight imperfection just make her look so adorable, especially with how it brought out the blue in her eyes.

"Well then Midoriya, shall we begin the final test?" She gestured to her milk chocolate with peanut butter inside. They look professional, with just the right texture on the chocolate so that it almost shined.

"Right then, you go first." He pushed his plate towards her, the chocolate covered orange slices and strawberries did look quite good. And from what he tasted he had done his mother's recipe justice. The chocolate should bring out the best of the fruit.

"Trying to make me seem eager?" Saiko asked nudging her plate towards him. "No, you will go first."

What? What was she talking about? That was so petty! But then if he ate her chocolate then he'd be eager about her cooking and, guh! Now this was a competition?

"You know." A dull tired voice dragged their attention to the back of the lab room where their permanently tired lab mate poured yet another cup of coffee for himself, the smug look he wore was nearly as bad as Saiko's but all in all, Hitoshi Shinso was actually an alright guy. "If you two are trying to prove that you two are in love or whatever the hell you are doing, you could always just feed each other the chocolate. That works right?"

Feeding. Saiko. Chocolate?

He looked at her. Her ears were red. As red as his felt. She looked twice as adorable at that moment as her zealousness was overcome by something else. She bit her lip, and grabbed one of her chocolate pieces and held it up for him. And he did the same.

They both moved slowly, matching the others pace as they slowly moved that bite sized piece of chocolate towards the others mouth. He felt Saiko's lips brush against his finger as she took a bite of the chocolate covered strawberry, his own lips touching her finger.

Did that count as a kiss?

Saiko's chocolate was good. Really really good. Even the peanut butter was amazing and just made him want to melt.

He could see her swoon slightly at his own chocolate, eyes fluttering and a soft but silent moan spreading through her body. His chocolate was just as good as hers it seemed. But at the same time. He couldn't admit that.

And she wouldn't admit that his was amazing either.

Results: Inconclusive, both of them wanting to do this experiment again.

**AN: This is so fun to write. **


	3. Chapter 3

It felt like forever since she had been to the lab.

There were many things that Melissa thought would be happening at the lab. There wasn't any running or smoke, so there hadn't been any fires, and the lack of officers told her there hadn't been any murders recently. Which was good. And covered the worst of her fears. Well, almost.

But more, realistically she wondered what the three quarrelsome lab mates of hers were up to. Seriously, how did she end up in charge of three of the smartest dumbest underclassmen in the entire world? Saiko was just naturally smart and worked hard to keep that up; even without her quirk, the girl was among the top scorers. Izuku had a stubborn streak that allowed him to tackle a problem and bash his head into it until it was solved or he gave up, to date, Izuku still hasn't had to do that. Then there was Hitoshi, he was a lazy, constantly tired asshole that somehow managed to get results.

"Why was I looking forward to coming back again?" Melissa felt her eye twitch and she pulled at her blond hair for a moment. Crap. She just had her hair styled too, and she was already trying to pull it out. But how could she not? She was in charge of three giant headaches! "Izuku and Saiko are probably arguing over something stupid - yet brilliant - and Hitoshi is going to be egging them on while smugly drinking his coffee!"

She stopped, looked around, and made sure that no one was looking at her. They were. Great. They were going to think she was insane. Which was probably par for the course. Right, well, time to find out what was happening in her lab.

She stomped up to the door and swung it open.

Sitting on the couch, smugly drinking his coffee and looking like he was up to no good was the purple haired Hitoshi, his legs were crossed and his laptop was sitting on the table forgotten. He gave her a small nod and nudged her gaze further into the lab. Oh great. Izuku and Saiko had to be arguing about something again. Those two were like-

They were holding hands. Izuku and Saiko were holding hands. Both of their faces were blushing so much that they each looked ready to pass out. While their hands were connected, the two of them were looking away from one another, attempting to work on some project or another with a stubborn look on their faces.

Melissa blinked. For a moment, she thought that Hitoshi had somehow glued the pairs' hands together, but that would just result in the two of them arguing over what the best solution for the situation would be while glaring at Hitoshi. No, this seemed voluntary. Which. which was, quite frankly, terrifying.

"Switch," Izuku muttered, just loud enough to be heard.

Melissa watched as the two separated for just a moment, then switched hands and resumed their usual tasks. Completely voluntarily. Did Hitoshi have a gun?

"Amazing, right?" Hitoshi muttered coffee less than an inch from his lips. "They've been at it for an hour."

Melissa blinked and looked at her watch. Was she in some alternate universe? No. Her watch was still perfectly in sync with the clock on the wall. Were Saiko and Izuku from another world? That was just about the only thing she could think of. Sure, she had known that Izuku and Saiko were, uhh, she didn't want to say that they were childhood friends, but they had a complicated history together, complicated in that they had the purest form of hate Melissa had ever seen but for some reason stubbornly stuck by each other.

She didn't want to say it. She really, really didn't want to say it. But there might be a small, ever so very small chance that they didn't actually hate each other?

No that couldn't be.

"So uhh, Hitoshi, what the fuck happened?" Melissa finally asked after gathering more than enough observable evidence to determine that her hypothesis of 'Shit is fucked' was valid and ready to be submitted to a committee.

Hitoshi made a noise that was part laugh, part groan, and leaned back, smiling like a proud father. "A few days ago, Saiko came in and accused Izuku of being in love with her. You can probably guess what happened next. Izuku refuted that, they started arguing, now they're gathering data to prove that they aren't in love."

Melissa wanted to open her mouth to protest everything Hitoshi said, but she couldn't as her mouth had already dropped upon hearing everything Hitoshi said. If she thought about it, then yes, there was a good chance that Izuku and Saiko were in love. They were just giant, stubborn jackasses about the whole thing and frankly refused to acknowledge their own feelings. Being in love would also fill in the missing piece of the puzzle about why the hell those two would even put up with being on the same continent as one another.

Really, the two of them could have gone anywhere in the world, but they both chose I-Island and they both chose the same lab. Her lab. Not only did both of them do all that but they almost always chose the same projects precisely so that they could fucking argue about it. The committee was in; Izuku and Saiko were in love with each other.

Which really just left her with one question.

"Fucking what?"

XXXX

This was proving difficult.

No matter how much she touted mind over matter, there was only so much control Saiko could exert over her own body. While her emotions appeared to have a great deal more impact. It was quite troubling. It didn't help that, try as she might, she couldn't quite get Izuku's pulse through his palm; not only was the pulse difficult to find there due to a lack of large arteries, but his skin was likewise thicker and rougher there.

That wasn't to say the sensation wasn't enjoyable. It was.

Just holding Izuku's rough hand was making it difficult to focus on her task. Additionally, she had bitten her lip several times since they started, and not on accident nor out of frustration - as much as it pained her to admit it - no, rather the act was because of just how much she was enjoying herself. The sensation was pleasant. She enjoyed feeling Izuku's rough, large, and sturdy hands enveloping her hands.

Whatever doubts or denial she had over her feelings over Izuku had been tossed to the side like invalid data.

She should suggest cuddling. She should very much suggest that. Just the simple idea of having Izuku hold her, even in a fixed position while he stubbornly denied having any and all feelings towards her despite all the obvious signs. Such as how long their experiment had gone on for. Already, they were minutes overdue and they hadn't stopped yet. Oh, it was just so cute! She wanted to watch him squirm while he attempted to ignore his obvious affection for her!

Just the simple idea was-

"That's a perverted face if I've ever seen it." Whatever thought Saiko had herself wrapped up in was shattered when the blond haired blue eyed woman that was their supervisor in the lab made herself known. Melissa Shield was leaning on Saiko's desk; the coy, knowing smile on her senior's face sent a chill down Saiko's spine.

And completely ruined the romantic mood!

Melissa was a constant thorn in Saiko's side, or at least that's what she originally thought of the woman. But after careful evaluation of her own feelings, Saiko confirmed that the reason why she didn't like the woman was because the woman talked to Izuku. Basically, she was jealous. But knowing didn't change her feelings.

It also didn't help that Melissa teased her like she was some kind of little sister!

"Oh," Saiko attempted to straighten her face and then relaxed her hand just enough to slip from Izuku's grasp. He squeezed tighter for just a moment. Well that was a good sign. Once her hand was free, Saiko crossed her arms and raised an eyebrow at Melissa. "You're back."

"Yep! I knew my adorable little lab sister must have missed me dearly."

"Hardly, I-"

Melissa grabbed Saiko's hand and pulled the girl out of her seat like it was nothing. Freak'n gorilla! "Come with me for a moment."

"Huh? What? But I-" Saiko stumbled as Melissa guided her into one of the adjacent rooms where they could have a bit more privacy. She wanted to protest that she wasn't done holding Izuku's hand, but that would be exposing her desire to continue doing so! Dammit! Why couldn't Izuku just confess to her already! Better yet, why wasn't Izuku protesting too! He was just looking confused. At his hand. Why was he staring at his hand!

He should be staring at her! She had her hair done up extra nice and her skirt was 1cm shorter than usual!

Saiko was pushed through the door with far more ease than she cared to admit. And was promptly locked in the storage room with Melissa Shield.

"So," Melissa moved over to her, a natural sway in her hips making the girl's blond locks bounce with the few steps she took. Her elbow slammed into the wall above Saiko despite both of them being about the same height, it was mildly terrifying. "Tell me everything."

"About what?"

Melissa flicked her in the forehead. "Your failing romance with Izuku."

Damn! Wait. "Failing?"

Melissa just sighed. "Honestly, it's almost cute how stubborn you are."

XXXX

Well shit.

Izuku stared at his hand and took a slow, steady breath. His heart was still pounding in his chest despite his best efforts. He glanced up towards the clock. Had they really held hands for that long? He hadn't gotten any work done. But that wasn't inherently a bad thing. Okay, it was a terrible thing. Instead, all he had managed to do was run a counter of all the times he wanted to do more than just hold hands with Saiko.

The list had started as a counter of the number of times he wanted to stop holding hands with her.

But that was quickly filled with nothing.

And now Melissa had shown up and taken Saiko into the storage room, ending the experiment, leaving him with indisputable evidence that he was at least probably mildly in love with Saiko. So his list included 127 accounts of wanting to kiss her, 58 counts of kissing her, 87 counts of holding her tightly, 10 counts of sex. The latter was likely skewed do to his own efforts to avoid that thought.

Arousal wouldn't help him in this situation.

No doubt that she knew that he was in love with her. And there was no doubt that Saiko was in love with him. Which left him with two choices. Get frustrated trying to avoid confessing to her while trying to get her to confess, or he could-

The storage room door opened with Melissa leading around a very flustered looking Saiko. It was kind of adorable. Okay, it was a lot of adorable. And satisfying. He wanted to hold her at that moment. 88 counts of holding her tightly. "Hitoshi! You're in charge of Izuku, get him in some clothes that make him look good."

"Ehh?" The lanky purple haired man stood and gestured towards his sweatpants. "Ehh?"

"I've seen you in a suit, and if I leave it to Izuku he'll be wearing a tanktop, lab coat shorts and flip flops!" Melissa pointed a finger towards him. She wasn't wrong, he currently was wearing just that. He was extra casual today so that Saiko wouldn't get the wrong idea. Besides, it was comfy. "Now man up and make sure Izuku looks decent by tomorrow."

"Why?" Hitoshi asked.

"These two are going on a date or they're going to be kicked out of the lab." Melissa shouted and pulled Saiko out of the lab and shut the door.

Izuku blinked.

A date with Saiko, huh?

Well, he could either get frustrated over it, or he could enjoy the ride and watch her squirm until she confessed.

Yeah, that sounded a lot better.

**AN: I could have made this a longer series with a lot of filler, but I decided that something of the short and sweet variety would be best. **


	4. Chapter 4

Despite I-Island being largely dedicated towards research and development there were a few places dedicated towards entertainment. There were many reasons for this, the first was that researchers that didn't do anything but research and develop all day resulted in uninspired products, the next was to entertain family and guests, and the last reason, was to promote romance between the young researchers. Despite its purpose being known, the romantic entertainment area was quite popular and effective.

More than one research study had been performed at the park, and couples that went on their first date at this particular one had a staggering 75% marriage rate.

Izuku licked his lips and checked his watch one more time. Saiko wasn't exactly late, but she wasn't exactly five minutes early like she normally was. Which meant she was late. No message from her either. He half expected her to cancel Melissa's insane demand of an experimental date and to stop taking it into the lab. Which was fair.

But he was fairly certain Melissa was enjoying playing matchmaker more than she cared to admit. Which was a lot because he asked her earlier if she was having fun. Her answer was yes.

Still, while it wasn't a true 75% chance that going here with Saiko would result in their union, the prospect of it was both frightening and appealing. While he did indeed accept his own feelings for Saiko and had resolved himself to enjoying watching her squirm while she tried to get him to confess, he was still uncertain about spending his life with Saiko. Yes, she was smart, yes, she was beautiful, yes, he was fairly certain that he loved her, but all of those things did not make for a relationship. He still had to deal with her rotten personality, an ailment that he wasn't certain had a cure.

An odd sensation tore through him. A desire to look to his left, there was no reason to, but he did. Almost like a primal instinct, drawing him towards his potential mate.

And for following that basic urge, he was rewarded.

Saiko was beautiful. That much he had always been willing to admit. But that beauty often had a cold smugness that made her unapproachable. But now, here a few meters away from him, he could feel the warmth of her beauty spilling outwards in waves towards him, what was different? Did she do her make-up differently? Well, yes, her lips were stained a more pink color, but that wasn't it. It wasn't in how she dressed, though that was as immaculate as ever, an off white blouse that hung low, though there was a black fabric that covered her cleavage, the sleeves were translucent, ending at her elbows, a dark blue skirt was highlighted by a light blue sash that went around her waist, exposing her long slender legs and the practical flats she had on. Nor was it her hair, he had seen her in a ponytail before, and it was as amazing as always.

It was her smile. Not just the smile on her face but the smile in her eyes as well. She was genuinely happy about this date. That smile was akin to the smile she wore whenever she triumphed over him, only it wasn't mixed with the sting of defeat. It truly was a simplistically beautiful smile unlike any other in the world.

If she kept smiling at him like that, he could marry her happily.

Now to see how she reacted to compliments.

Izuku put on his best smile, it wasn't forced, nor was it mockery, it was simply a smile that expressed his joy of seeing her, a true genuine joy at seeing Saiko. That felt as wrong as it did right. His smile only grew when she stopped a few feet away from him, the wind catching her hair and her blue shining through her makeup, both of her hands grasped her purse strap tightly and her eyes were wide. Apparently his smile had a similar effect on her.

And he hadn't even told her she looked beautiful.

"Saiko," He nodded, keeping up the smile. She jumped at hearing her name. "You look more beautiful than usual, did you really go all out for this date?"

"Of course!" She half shrieked her face glowing red. Saiko took a moment and gathered herself. "Of course I did. Just because I'm on a date with you and this date is purely experimental does not mean I would allow my appearance to slouch."

So she says, but even he could tell this was beyond her norm. Maybe Melissa helped.

"And I would like to thank you for dressing the part as well." She took a step closer to him and nodded at his outfit. His outfit consisted of a white button up shirt that breathed well and was tight around his chest, a pair of pants that ended above his ankle and some new shoes. "Now shall we get started?"

"Absolutely, would you like to hold my hand now, or do we have to work up to that?" He held out his hand to her waiting for her to take the bait.

Saiko stared at it for a moment, her hand inching towards his before she stole it back. "You'd like that, wouldn't you?"

"It's part of the dating experience, is it not? I thought you wanted to do this right." He withdrew his hand, trying not to let his amusement show on his face. If he had to classify Saiko, she would be a Tsundere through and through.

"Wait, I," Her eye twitched. She lunged for his hand and did more than just hold it. She wrapped her arm around his and entwined their fingers. "We're going to do this correctly."

"Right then, let's get started on this date. When you fall in love with me, just let me know."

XXXX

"This is bullshit."

Melissa groaned and rolled her eyes, turning away from one of the cameras she was using to spy on Izuku and Saiko. Hitoshi was complaining. Again. It seemed that unless he was actively relishing in someone's torment that he was complaining. Which made him a rather annoying lab partner. "What now?"

"Huh?" Hitoshi looked up from his phone and looked at her with surprise. He turned it slowly and showed off the came he was playing. "Oh, someone was-"

"Shouldn't you be monitoring Izuku's and Saiko's vitals?" Melissa asked tapping her foot onto the ground.

"Shouldn't you be minding your own business?" Hitoshi retorted rolling in the chair over to the computer. "They're doing all the usual stuff when they're together. Besides this data is for them to argue, not for you to-"

"Guh, fine, I'll stop meddling."

"What? No keep doing that, just let me enjoy watching the shit show." Hitoshi stretched in his seat. "Really though, if you're trying to get them together, I legit don't think you'll have to worry."

"Oh?" Melissa crossed her arms and let the sass channel through her body. "And what makes you say that?"

"Because, while Saiko is all over the place, Izuku is calmer at the moment. He's in control, has been from the start, this experiment is going how he wants it to go. He's got Saiko's number. I think he would have gotten around to this without you sticking your butt into it." Hitoshi said in a drull pulling out his phone again and swinging the monitor towards Melissa.

"And what makes you so certain?" Melissa muttered glancing at Izuku's numbers. He was much calmer than Saiko, but that was normal. Saiko just operated in a naturally high strung state.

"He told me his game plan when you forced us to get him dressed." Hitoshi spun in his chair putting his back towards her. "Don't be surprised if something unexpected happens."

XXXX

Even if she was in love with Izuku, there was no way that she ever would have thought him capable of being actually romantic. Not only was he not arguing with her, even when she tried to poke and prod him into doing just that, but when she won some of the games, he just smiled and congratulated her.

And he didn't even seem upset by it.

What did it mean? What on earth did him being so nice, so supportive, so, so, so, so she couldn't even think about what he was being! It was like he really was her boyfriend right now and they were just going on another date! And she was actively trying to make him lash out at her.

Okay, she knew that she was a bit of a bitch, but this just felt cruel.

Very cruel.

"Hey," Izuku touched her shoulder slightly, she could feel his warm hand through the sheer fabric of her sleeves. His touch was almost enough to make her shudder, and more than enough to make her smile. "You feeling alright?"

"Why?" she felt her anger growing, but then stopped herself. Izuku didn't mean anything by that. He was showing her genuine concern. Which was amazing. He had done it a few times before but this was different. "I'm," she took another breath and smiled at him. "I was just lost in thought, why?"

He pointed towards one of the docks, towards a swan shaped paddle boat. "I wanted to know if you want to go out onto the lake for a bit."

Saiko blinked at the cute little boat. "That sounds like a cliche where we both end up falling into the water."

"Ha, don't worry, we'll be fine, I think between the two of us, we can figure out how to safely operate a paddle boat." Izuku held his head high, his shoulders back and a soft but brilliant smile on his face. With how Izuku looked right now, he was certainly eye candy, and she was well on her way to getting eye cavities. Seriously, it felt like she was swooning every ten minutes or so.

"I certainly hope so." She gestured towards her outfit, "While I do enjoy swimming, I don't think I'm properly dressed for that."

She caught him, just the faintest blush, but she caught it, she thought about bringing it up, but stopped. That would be getting in the way wouldn't it? Or would that simply be teasing? But then Izuku grabbed her hand. Stealing her breath and making her blush all the more.

They walked over to the rental boat and got in it with some difficulty, and then paddled out into the middle of the lake. It was a nice trip, the water clear and they could see several of the underwater facilities that dotted the lake shore. But being on the water, alone, with Izuku, constantly brushing up against him, and finding it so easy to be happy.

To be in love.

Was making her just so at ease.

"You know," Izuku stared out over the shore, and then brought his gaze over to hers. She didn't trust that look in his eyes, nor that soft smirk of his. "Being, alone, out in the middle of this lake is pretty romantic right?"

"I agree with your hypothesis." She muttered, unable to look away from him, if anything she was being drawn in closer.

"We should kiss."

She had never agreed with him more.

She didn't even care that she was the one to kiss him. It was worth it. She could feel herself melting into the kiss, her body sending signals to her mind that this was good and that she wanted to do this a lot more.

They parted for too soon. Stared at each other for far too long. Then she spoke up. "Well?"

Izuku blinked. "Need more data."

He kissed her again. And she agreed. They needed a lot more data.

A lot more.

**AN: Hope you all enjoyed. **


	5. Chapter 5

She had done it. She had finally broken Izuku. That tall, proud, muscular, man of science had finally given in to his base instincts and was now fully expressing his desires for her. And she was receiving that desire readily. His hand held hers above her head, keeping her against the wall, while the other was grabbing onto where her waist met her hip, even through the clothing he was trying to grab greedy handfuls of her body.

The date had started out as a test. But they had been so wrong in what it was testing. It wasn't testing their love, their compatibility, rather it had been testing their patience. How long could they keep their hands off of each other when they were so desperately pushing each other into acting.

At the end of their experiment, Izuku had grabbed her hand, the one still above her head, the one he hadn't let go of, and pulled her through the streets towards his apartment. Only once they had their privacy did all of this start in a new and wonderful way.

Izuku was kissing her.

And she was kissing him back. Their combined desires for each other had finally reached the boiling point and they were now venting that steam in the only way they could. Not with words, thoughts, or talk, but with the baser more primal way of communication that made her head spin.

Contact.

Physical.

Intimate.

Contact.

Saiko tangled her fingers in with his, holding his hand tightly while she finally got the chance to run her hands through his long tangled green hair, the sensation was almost as wonderful as the kissing was But the moan he let out when she pulled his hair just the slightest bit, that was the real kicker. His unquestionable primal desire for her was intoxicating.

Her body reacted in kind, a moan escaped her as she felt his hand move to her exposed thigh, and traveling upwards.

A spark of fear coursed through her body. Just once. Just for a second. The realization that tonight, mere hours ago when her only goal was to get Izuku to admit that he loved her, that she was now going to have sex with Izuku. It wasn't a question of if, just a matter of when. That fear was replaced with an eagerness when Izuku kissed her neck.

She had nothing to be afraid of.

This was Izuku, someone that had been in love with her for years, and someone that she had loved for years. The more she thought about it, the further back those feelings had permeated, at this point she was ready to admit that her initial competitiveness with him had been nothing more than a ploy to get him to notice her.

"Admit it," Izuku's voice was low, hungry, and filled with energy. His hand grazed her bare stomach while he gave her collar bone a searing kiss that sent her body roiling in delight. Every single kiss made her more than ready for him. They finally stopped holding hands and he grabbed her waist with both hands. Another hungry kiss that was far too primal for someone as in control as Izuku.

Though perhaps all of this was him in control, and he was begging for the key.

Saiko pressed her back against the wall, giving herself just enough room to look at Izuku and those verdant eyes of his that were glaring at her with pure desire. How did she look to him, was she just as eager? Could he see everything that she saw in him? Why did they stop, they could be kissing more, more, more.

"Admit what?" She asked, hands grabbing onto his wide, powerful shoulders. She wanted to jump up, make him catch her, wrap her legs around his waist and kiss him. She wanted to kiss him, over and over again. There was no need for further experimentation, anything more would be a farce. Their desire was real.

Izuku was the only man in the world she wanted to be with.

"That you want this." Izuku's voice was low, barely more than a breath, his hands doing wonderful things just underneath her shirt, his large thick hands were making her increasingly aware of just how much she desired everything from him. She never wanted him to stop touching her. "That you're as crazy about me as I am for you."

"If I do?"

He leaned in, breath tickling her ear and making her entire body shudder. He reached down and grabbed onto her thigh, lifting her leg up and giving her the chance to do what she had been dreaming of for what felt like years. Her legs wrapped around his waist, his hands grabbing her ass while she grabbed his head and kissed him deeply. This test had proven to be beyond what she had envisioned.

"If I do," she breathed, barely long enough to kiss him again. "If I do, will you take me to your bed?"

Izuku groaned in response, his back slamming against his wall while he stumbled towards that glorious destination.

"If I do, will you strip me naked?" She asked, hands moving to her top and pulling it off, exposing the frilly black underwear she had carefully selected for this date. Her back touched his cold wall once more, his kisses greedily touching her now exposed chest.

"If I do-"

"When you do, I will kiss you," Izuku stated, kissing her on the neck. "I will take you to my bed, I will strip you naked, and then." His breath was a low fiendish growl. "We will make love."

"And after that?" she moaned, his lips trailing on his neck, extinguishing any doubts she had about this. "After we fully admit that we're in love, then what?"

"We act on that love." He growled, biting on her bra and pulling her into his bedroom. He half placed, half threw her onto his bed and loomed over her, kissing her again and again. Her hands were busy unbuttoning his shirt. She wanted to feel those bare muscles of his. "We date. Confirm that love night, after night." His kiss lingered for a moment. "After night. Then, I ask you to marry me."

"I like your apartment," she blurted out, eyes fixed on his now bare chest as he tossed his shirt to the side. "We should live here."

"Agreed."

She started to work on her pants, wiggling her hips as she continued to lay on his bed. "Children."

"Now?"

"I want two. Hopefully a boy and a girl."

"Agreed."

Her pants were tossed to the side, her shoes were somewhere else. Izuku's shorts fell down, revealing his glorious nude body to her. As base as it was, seeing him nude just made her all the more eager to have sex with him.

He unhooked her bra with skills that made her head spin, tossing the garment that she had spent ages deciding on to the side like it was nothing more than a dirty sock. Even the matching set of underwear was little more than a distraction.

Her breath came in short hot gasps as Izuku took this time to explore her body. His fingers moved along her skin like precision instruments, locating sensitive areas for his mouth and tongue to explore. He took a deep, needy kiss of her right breast, his hand squeezing her left breast as she moaned.

A kiss on the underside of her breasts.

A kiss on her stomach.

A kiss on her belly button.

A kiss even lower.

A kiss on her thigh.

A kiss on her vaginal lips.

A hot, wet tongue going in just a bit.

"Wait!" she half moaned half screamed, fingers digging into his sheets as she prepared her now naked self for him. She would never be ready for this. But that's what first times are for. To make sure that she would be ready for the next time.

Izuku looked at her, silent, still, and curious. He was in control.

"Be gentle."

He nodded.

When his hand pressed down into the sheets beside her, her body reacted, she had been desiring this, all of this, for so long that her body was way too eager for what was about to come. Izuku was gentle, reaching up for her face and touching it softly, giving her yet another kiss before trailing his hand downward, stopping only to grab her breast for just a moment before holding onto her hip.

He angled her slightly, opened her up, just the slightest bit. And then.

Insertion.

For the next few moments, she was silent, her entire body simply tensing and not listening to her brain as Izuku pressed further into her. As much as it hurt to feel all of him slide into her like that, it also felt good. It would have been worse if he had pressed much further, if he hadn't been so gentle. But Izuku was gentle. Those green eyes of his were scanning over her body, watching her every reaction as he entered her and his hands were rubbing her body in so many amazing ways.

So this was sex.

So this was sex with Izuku.

So this was sex with the man she loved.

Izuku moved slowly, the initial pain fading as the pleasure of the act began to fill her completely. She could feel everything down there, Izuku's long, hard penis moving with a deliberate motion while his hands took greedy handfuls of her bountiful chest. She had never felt so beautiful, so alive, so in love.

He kept up that slow, gentle motion, one hand keeping her hip in place, the other guiding her, each and every thrust making her feel like she was floating. The pain was gone, and the pleasure remained. But it wasn't enough.

"Izuku." She moaned, barely able to get so much as his name out without wanting to scream it. "You can go fas-"

She didn't even have the time to finish that statement as she was sent into a deep body filled moan that had her back arching, hands grabbing at the sheets and pulling. Izuku had understood her though, and grabbed onto her hips with both hands, and began to move faster. Just a bit, but the next thrust was faster than the last. Faster, faster, faster, deeper, so much deeper, his entire length was pulsing in and out of her, stealing her breath away and making her eager for more, more, more.

Her head felt like it was spinning, and her entire body felt both tense and relaxed at once. She could feel it coming. She knew what it was, her experimentations with masturbations were enough to make her recognize the feeling. An orgasm.

But it had never felt like this before. It had never felt so good. So forceful. So there. Where before it felt like just a splash in a pool, this one felt like a wave of unending pleasure coming barreling towards her.

"Izuku!" she screamed, her body tensing up. She wanted to kiss him. She wanted to kiss his face. She latched onto him, her body screaming as every single muscle contracted and relaxed at random times. It felt like she was falling, falling, falling, and then stopping for just a moment. She brought her face up to his and kissed him, her spasms subsiding for just a moment. He was still so hard inside of her. "I believe that you won this round."

"It wasn't a contest," he informed her, hands now on her ass. He moved his legs slightly so that she was sitting on his lap. "It's a collaboration."

"I don't think that's supposed to be sexy, but it really turned me on," she laughed, then squeaked, when his hips started to move up into her. It was completely different from when she was on her back. "What?"

"You can keep going right?"

She nodded. Apparently, it was easier for her to get off than it was Izuku.

But after two more orgasms, and losing her ability to walk for the next day, she finally felt what it was like to have Izuku's semen fill her up. It was a sensation she might become addicted to.

XXXX

Honestly, he didn't see this coming at all.

Sure, he wanted to kiss Saiko before the end of the date. But he didn't expect to drag her home and then makeout with her, stripping her down, seeing her naked, and removing all of their stubborn pride from each other that had been getting in the way of their relationship, resulting in sex.

He didn't even know if it was comparably good sex, nor did he care to find out. He finally had what had been missing from his life for years. Saiko in his arms, ready to kiss him at a moment's notice. Right now they were laying in his bed, the sex soaked sheets covering their naked bodies as they only half watched whatever Saiko had selected from Netflix.

Oh. RiIght.

They were already in a relationship, so it really didn't matter if he let her have this one victory. "Hey Saiko."

"Hmm?" she smiled up at him, her lavender eyes fluttering for a moment.

"I love you." He kissed her on the top of her forehead and pulled her closer. Then she swatted him in the chest.

"Hey! No fair! Guh! Now you're the first one to confess!"

"Are you serious right now?"

"Not at all." She kissed him again, then nuzzled her face against his chest. "I love you too, Izuku."

**AN: The end! Hope you all enjoyed this one! *Before you bitch about rushed endings, yes, these stories are short, they're designed to keep me sane while I work on longer projects***


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